Power supply and fixing structure of heatsink and circuit board applicable to the same

1. A fixing structure of a heatsink on a circuit board on which a wiring pattern is formed, wherein an electronic component is installed on the circuit board in an upright position; the heatsink has a U-shaped cross section, with a base and first and second substantially parallel legs extending from edges of the base, the heatsink being attached to the circuit board in an upright position so as to closely contact the electronic component for radiating heat generated from the electronic component; the heatsink has a component fixing face defined by a front face of the first leg on which the electronic component is fixed, the second leg not receiving a component, and a board contact face defined by a bottom face of the base which is orthogonal to the component fixing face and in direct contact with the circuit board; the component fixing face and the board contact face having a common cut out portion defined by contiguous portions of the base and first leg to prevent interference with terminals of the electronic component; the board contact face of the heatsink has a first rivet insertion hole through which a tip of a rivet penetrates; the circuit board has a second rivet insertion hole provided at a position corresponding to the first rivet insertion hole of the heatsink and a land portion provided on a periphery of the second rivet insertion hole so as to come into direct contact with an end portion of a flange of the rivet inserted into the second rivet insertion hole, the land portion having a diameter substantially equal to and slightly larger than a diameter of the flange end portion; the land portion is connected to a grounding line of the circuit board; and the heatsink and the circuit board are held by the rivet inserted into the first and second rivet insertion holes, between the flange end portion and a tip crimped portion of the rivet, and the electrical connection between the grounding line of the circuit board and the heatsink is ensured via the rivet, wherein a gap is formed between the flange of the rivet and the land portion of the circuit board connected to the grounding line, the gap being filled with solder dip material.

2. The fixing structure in accordance with claim 1 , wherein the heatsink is made of aluminum and the rivet is made of a material which can be soldered; and the land portion is electrically connected to the end portion of the flange of the rivet with certainty by using the solder dip spreading through the gap between the land portion, the flange end portion of the rivet and their peripheries.

3. A fixing structure of a heatsink on a circuit board on which a wiring pattern is formed, wherein an electronic component is installed on the circuit board in an upright position; the heatsink having a U-shaped cross section, with a base and first and second substantially parallel legs extending from edges of the base, and being attached to the circuit board in an upright position to closely contact the electronic component for radiating heat generated from the electronic component; the heatsink having a component fixing face defined by a front face of the first leg on which the electronic component is fixed, the second leg not receiving a component, and a board contact face defined by a bottom face of the base which is orthogonal to the component fixing face and in direct contact with the circuit board; the component fixing face and the board contact face having a common cut out portion defined by contiguous portions of the base and first leg to prevent interference with terminals of the electronic component; the board contact face of the heatsink having a first rivet insertion hole through which a tip of an iron rivet penetrates beyond the board contact face; the circuit board having a second rivet insertion hole at a position corresponding to the first rivet insertion hole of the heatsink, and a land portion provided on a periphery of the second rivet insertion hole coming into direct contact with an end portion of a flange of the iron rivet inserted into the second rivet insertion hole, the land portion having a diameter substantially equal to and slightly larger than a diameter of the flange end portion; the land portion being connected to a grounding line of the circuit board; and the heatsink and the circuit board being held by the iron rivet inserted through the first and second rivet insertion holes, between the flange end portion and a tip crimped portion of the iron rivet, the iron rivet providing the electrical connection between the grounding line of the circuit board and the heatsink, wherein a gap is formed between the flange of the rivet and the land portion of the circuit board connected to the grounding line, the gap being filled with solder dip material.